JBL Releases Updated Iconic JBL L100 Speakers

[Swerd]

Here is Dennis's frequency response curve of the L100A with it's original crossover (the speaker sat vertically for this):

And here is the same speaker with Dennis's crossover (again, the speaker was vertical):

Old crossover schematic (Note there is an error in my drawing, the midrange driver should show opposite polarity to what appears.)

And Dennis's new crossover schematic (all driver polarities are shown correctly):

 

[Swerd]

Thanks Swerd. That clears it up. It's strange that they would have abandoned the in-line driver configuration for the more helter skelter arrangement that introduced all kinds of interference effects between the drivers, which was exacerbated by the fairly shallow crossover slopes. The professional studio monitor looks even worse. Kind of scary that they were so popular in recording studios.

According to what I learned, that helter skelter arrangement was deliberately chosen to allow owners to position their speakers either horizontally or vertically.

 

[<eargiant]

During the 1970s, JBL had four different models that use the same or similar drivers and cabinet. From left to right in the photo (in reverse order of their introduction) are the 4311, L100A Century, L100 Century, and 4310.

The oldest design is on the right, and each newer version appears to it's left. The 4310 and 4311 were the pro studio monitors, and the L100 Century and L100A Century were the commercially sold versions. They all shared the same or similar versions of 123A woofers and LE5-2 mid-range drivers, but had different tweeters, the LE20 in the 4310 and L100 Century, and the LE25 in the L100A Century and 4311.

The L100 Century had the vertical alignment of drivers, and had a crossover network of sorts:
View attachment 23326

My speakers that Dennis used to design his new crossovers were the L100A Century. They had a much simpler network:
View attachment 23327

I hope I got all this right and explained it clearly.

And finally, Dennis's new crossover for the L100A is fully described here https://forums.audioholics.com/forums/threads/the-vintage-jbl-west-coast-sound-becomes-the….25014/.

The furthest to the right is the 4310 Control Monitor and the in-line driver version L100 to it's left is basically the home version of the 4310. All the drivers on these had Alnico magnets. I preferred the sound of this version.

The third one in from the right is the mid version of the L100A (black label) which is the equivalent of the 4311 Control Monitor which is the last one in the picture.

The final version of the L100A with the orange label are not shown in this picture. If memory serves me the pro version of these was the 4311B but I'm not 100% sure. I believe that by this point all drivers had ferrite magnets.

 

[<eargiant]

I posted this in another thread but it's pertinent here too. This is Bruce Swedien with his beloved JBL 4310's. He had several pairs of these and for years would lug them around to all of his recording gigs.

 

[Swerd]

This is Bruce Swedien with his beloved JBL 4310's.

Indeed, that photo shows his monitor lying on it's side. Thanks .

 

[<eargiant]

Even audiophile favorites were mixed on these less than perfect speakers. Check out the L100 (egg crate grill) perched on the left side of this shot of Steely Dan in the studio.

Love it or hate it, there's no denying that it's definitely an iconic speaker...

 

[lovinthehd]

Thus the West Coast Sound for so many iconic recordings?

 

[zieglj01]

Thus the West Coast Sound for so many iconic recordings?

Loud and bright -- however, many liked it that way

 

[lovinthehd]

Loud and bright -- however, many liked it that way

Worked fine at the time. Looking for a list the top result was Swerd's thread

 

[zieglj01]

Worked fine at the time.

Worked fine and good for JBL and their market -- and they made some money. A lot of so-called silver and golden ear fan club members have enjoyed some of them JBL speakers and the like in the past. Audio is subjective and it is about what floats your boat -- and enjoy it.

 

[sterling shoote]

Worked fine and good for JBL and their market -- and they made some money. A lot of so-called silver and golden ear fan club members have enjoyed some of them JBL speakers and the like in the past. Audio is subjective and it is about what floats your boat -- and enjoy it.

+
JBL's float my boat, not only sound right to me, over all others to price point; but, they seem to work at concert sound reinforcement levels without force or strain. It's one thing that appealed to me back when I initially heard a pair of L100's. I have been satisfied with my L100t3's for 30 years.

 

[mp54]

Am currently using a set of L100s in a system featuring two 40 watt tube Dynakit MkIV amps. The original LE25 tweeters were replaced by 035Ti years ago (at the time JBL had ceased production of the LE25 and recommended the 035 as replacement). Foam grills disintegrated years ago. I bought mine in 1975, as I recall. Might have been '76. I've gone through multiple speakers, including electrostatics, but the L100 has always been my favorite. I may buy these new ones, too. Probably outlive me.

 

[everettT]

Loud and bright -- however, many liked it that way

Is that why Bluegrass fans preferred east sound

 

[mp54]

FWIW. the 4312SE sells for 2500/pr. It appears to be the same speaker as the new L100, but without nice cabinetry, no 3D grill cover, and different driver placement. So I guess JBL is charging 1500 dollars for the foam and woodworking. Maybe there are more substantial differences, don't know

 

[lovinthehd]

Loud and bright -- however, many liked it that way

Is that why Bluegrass fans preferred east sound

I never thought of the L100s as bright at the time. May have just been as opposed to other offerings; many other offerings just seemed a bit slack....but subjective experiences can be hard to convey. At this time many had wild contortions of the bass/treble knobs or even a graphic eq, too....

 

[Verdinut]

The nostalgia thing was interesting briefly but 4k/pr? Yow.

They're meant for playing back 4K video sound tracks!

 

[mp54]

I never thought of the L100s as bright at the time. May have just been as opposed to other offerings; many other offerings just seemed a bit slack.....

I think that is generally correct. I remember going to hi-fi shops and comparing. The big thing then was the AR3 series of speakers (and Bose, of course). AR's claim to fame was bass, which hitherto required a large box or a horn, etc. The AR3 sounded, to me, completely lifeless. No detail or definition. I guess you could call it smooth, or refined, or balanced, or whatever. But it didn't sound like what I wanted to listen to. The L100 sort of "jumped out" out at you, and reminded me of something live. I don't think it was "accurate", but what was, back then? And what is, now?

In one of my systems I have a set of L100 (bought in 1975) that I use with hand built Dyna tube monoblocks, along with a more "modern" hand built tube preamplifier. Sure, It sounds like old school hi-fi. But I've given up on trying to get the "Absolute Sound" of live instruments in my home. And I've gone through them all, including electrostatics. Now I'm back to late '60s and early '70s. My listening is mostly classical and jazz. Not the heavy rock thing. Go figure. PS: if you like the classic JBL monitor sound, google Kenrick Sound. An outfit in Japan that rebuilds old JBL monitors. They have some interesting YT videos of their work.

 

[Swerd]

I think that is generally correct. I remember going to hi-fi shops and comparing. The big thing then was the AR3 series of speakers (and Bose, of course). AR's claim to fame was bass, which hitherto required a large box or a horn, etc. The AR3 sounded, to me, completely lifeless. No detail or definition. I guess you could call it smooth, or refined, or balanced, or whatever. But it didn't sound like what I wanted to listen to. The L100 sort of "jumped out" out at you, and reminded me of something live. I don't think it was "accurate", but what was, back then? And what is, now?

In one of my systems I have a set of L100 (bought in 1975) that I use with hand built Dyna tube monoblocks, along with a more "modern" hand built tube preamplifier. Sure, It sounds like old school hi-fi. But I've given up on trying to get the "Absolute Sound" of live instruments in my home. And I've gone through them all, including electrostatics. Now I'm back to late '60s and early '70s. My listening is mostly classical and jazz. Not the heavy rock thing. Go figure. PS: if you like the classic JBL monitor sound, google Kenrick Sound. An outfit in Japan that rebuilds old JBL monitors. They have some interesting YT videos of their work.

You seem like a perfect candidate to build the new crossovers for your L100s. If you aren't far from the Maryland/Washington DC area, you should come listen to mine. The new crossover cures most of what ailed the original JBL design. No one I know of who actually built these crossovers wanted to go back to the old ones. That included one guy who went to the effort of building elaborate internal switches that allowed him to quickly switch back and forth between the old original crossover and the new one.

 

[MrBoat]

Always liked the L100's. The peaks and dips managed to work with what avg listening rooms consisted of back when they were developed. Back in the 70's, the average family home was at least 1000sq ft less than what it is today with double the amount of ppl in them. Rooms were separated by walls and narrow doorways for the most part. Heavily sculptured or heavy shag carpets, large padded furniture and clutter on or, up against the walls, heavy drapes and what not. A lot of antique architecture was still abundant with a lot less insulation in many cases.

Trying to apply a speaker like the L100 in todays oversized spaces is erroneous at best. Is one of the first considerations I have to visit when reading what people are trying to accomplish with audio these days. That I still have a humble 60's-70's home and almost nothing that is discussed with audio applies to it. Speakers like the LS3/5a etc. sounds wonderful in here without much input from me.

 

[mp54]

You seem like a perfect candidate to build the new crossovers for your L100s. If you aren't far from the Maryland/Washington DC area, you should come listen to mine.

Thanks for the offer, but I'm too far away, and probably too far gone as an audiophile. I like living in the past.